As shown in the "Display Driver Handbook", published by Texas Instruments, 1983, electroluminescent (EL) displays have recently attracted significant interest as an alternative to cathode ray tubes (CRT) as visual output devices in electronic systems. Unfortunately, because of the capacitive nature of EL displays as explained by Miller and Tuttle in "A High-Efficiency Drive Method for Electroluminescent Matrix Displays", Proceedings of the SID, Volume 23/2, pages 85-89, 1982, the power consumed by the overall display system is highly dependent on the circuitry used to drive the display.
Various schemes have been disclosed to provide drive circuits which are designed to match the capacitive characteristics of the EL displays. Miller et al. in U.S. Pat. No. 4,349,816 issued Sept. 14, 1982 have shown the use of a capacitive voltage divider circuit, while Hochstrate in U.S. Pat. No. 4,238,793 issued Dec. 9, 1980 and in U.S. Pat. No. 4,253,097 issued Feb. 24, 1981 has shown the use of LC resonant tank circuits with an oscillating drive to power the EL display elements in displays with very few matrix elements. Although each of these prior schemes is relatively efficient for driving an EL display, they suffer from several problems of their own such as being overly sensitive to variations in the capacitance of the EL display, requiring a relatively large number of individual capacitors which are difficult to fabricate as an integrated circuit, being impractical to realize when a large number of matrix elements (i.e., on the order of one hundred or more) is to be addressed, or being too slow to permit rapid activation (i.e., at 60-70 hertz) of the entire EL display when the display has a large number of matrix of elements.